All the following assess the water-quality-criteria for water pollution are all EXCEPT:

(Dissolved nitrogen): Ref: (629-30-Park 20th)CHEMICAL CRITERIA FOR WATER - QUALITY(a) Nitrites - should be zero in potable waters, their presence indicates pollution of RECENT origins.(b) Nitrates - There presence indicates one OLD contamination, Nitrates in water should not exceed 1 mg/L(c) DISSOLVED OXYGEN - This should not be less than 5 mg/L(d) Free and saline ammonia - This is an excellent indicator of sewage contamination of RECENT origin.Free and saline aminonia should not exceed 0.05 mg/L in drinking water(e) Chloride - The standard prescribed for chloride is 200 mg/L, The maximum level is 600 mg/L(f) Hardness - The total hardness should not exceed 0.1 mg/L(g) Albuminoid ammonia - In potable water should not exceed 0.1 mg/L(h) Oxygen absorbed - The oxygen absorbed at 37degC in 3 hours should not be more than 1 mg/L* Water with concentration of total dissolved solids below 1000 m/glitre is usually acceptable to the consumers (> 1200 mg/L unpalatable)